An assembling operation of an optical connector sometimes involves a fusion splice between a built-in fiber of a ferrule member and an optical fiber of an optical cord by means of a fusion splicer. In the fusion splice a tip of the built-in fiber and a tip of the optical fiber need to be arranged opposite to each other and, because the ferrule has the very small diameter, e.g., about 2 mm, it is difficult to handle it with bare hands. Therefore, a ferrule holder for holding the ferrule member is used in execution of the fusion splice between the built-in fiber and the optical fiber (e.g., cf. Patent Literature 1)